There are many different types of fibers which are used to form various fabrics. One such fiber is polypropylene. Polypropylene is inexpensive and can be easily solution dyed. Further, it does not readily stain and thus it is particularly useful in applications such as table cloths, placemats and afghans or throws. One disadvantage of polypropylene fibers is that the fibers themselves have a very low coefficient of friction. Thus, once woven together they do not naturally remain bonded together, particularly if placed in a washing machine.
In weaving, for example, table cloths, placemats and afghans (throws), it is frequently desirable to leave the edge portions unraveled to form a self-fringed fabric. This is usually done for aesthetic purposes. However, due to the inherent nature of polypropylene fibers, they are unsuitable for such applications. When placed in a washing machine, they would unravel.
There are many ways to overcome this problem. The edges can be woven together so that they are not in an unraveled state. Special stitching can be used to bond these unraveled edges together, preventing the fabric from further unraveling, but this is expensive due to additional labor expense. It is also possible to simply melt the edges of the polypropylene together, preventing unraveling. But this is particularly unattractive.
There have been many attempts in the past to incorporate hot-melt adhesive-coated fibers or thermoplastic fibers and use the thermoplastic nature of the fibers to bond woven fibers together. For example, Dickey U.S. Pat. No. 1,854,693 describes securing selvages by melting edge threads using solvent or heat. Scruggs U.S. Pat. No. 2,840,117 employs thermoplastic threads. Further, Westhead U.S. Pat. No. 4,467,839 discloses using thermoplastic weft strands which are melted to fill in gaps in papermaking fabric. Bryant U.S. Pat. No. 4,774, 135 discloses coating a glass strand with thermoplastic material to bond woven glass fibers together. Unfortunately, none of these methods would be particularly suitable for use in the present invention.
Typically, glass yarns which incorporate an adhesive are not designed for applications which require a particular aesthetic appearance and are to be used next to skin. Mueller U.S. Pat. No. 4,502,513 discloses weaving the binding fiber along an edge. It is particularly useful for forming straps of material such as safety belts. But, again, this would not be useful in making a placemat, table cloth or afghan (throw).
The solution provided by the Dickey patent is particularly unacceptable. This reference suggests melting the fibers themselves to bond the edges together. This would be very unsightly and particularly unacceptable for polypropylene fabric formed basically from totally polypropylene fibers.